Preparation of levalbuterol hydrochloride

Abstract

Provided are processes for the preparation of (R)-SLB.D-DBTA salt and levalbuterol hydrochloride. Also provided are levalbuterol hydrochloride degradation products and processes for preparing them. Pharmaceutical compositions comprising at least one levalbuterol hydrochloride of the invention and at least one pharmaceutically-acceptable excipient are also provided.

1 - 22 . (canceled) 
     
     
         23 . Levalbuterol hydrochloride characterized by at least one of an enantiomeric excess of at least about 99.8%; having less than about 1700 ppm of residual C 1 -C 4  alcohol; or having a pH of at least about 4.3 in 1% aqueous solution at room temperature. 
     
     
         24 . The levalbuterol hydrochloride according to  claim 23 , wherein the residual alcohol is methanol. 
     
     
         25 . The levalbuterol hydrochloride according to  claim 23 , wherein the pH is about 4.5 to about 7. 
     
     
         26 . Levalbuterol hydrochloride characterized by at least one of having less than about 0.15% by area HPLC of at least one of Compound A, Compound B, and Compound C; having less than about 0.10% by area HPLC of total unknown impurities; or having less than about 0.25% by area HPLC of each impurities including Compound A, Compound B, and Compound C, after being stored for three months at 40° C. and 75% relative humidity. 
     
     
         27 - 28 . (canceled) 
     
     
         29 . A pharmaceutical composition comprising a therapeutically effective amount of the levalbuterol hydrochloride according to  claim 26  and at least one pharmaceutically-acceptable excipient.